User Xelloss originally started translating the software to Chinese before working on the Celsys' official translations. He's not as active these days but maybe you could contact him for information about a Chinese translation?We'd all use SDL Passolo for the text strings and then the L10N to re-pack text/images back into the language files.

The creator of the L10N (VADUEX) could be found at yox.cc forums... but it seems the entire site is now dead :\ I think the last version we have is L10N 3.3.1 (and hopefully it will continue to work with the next version of CLIP also!)

There's no specific tutorial for the translation as the whole setup is quite complex and convoluted. Ideally we'd put the translation on Git hub and run it openly... but so much of the translation depends on CELSYS' copyrighted data files and it also circumvents their license protection by changing the language. It's a very grey area :L